Country. Gender. Age bracket. Creative Name. Angle. Targeting. Bidding mode. Ad type
Just mangle them. There is no way to hide querystrings from people who want to find them.
Country doesn't matter - your ads are targeted based on IP geolocation so it's obvious what country you are targeting.
Gender... just put A for guys and B for girls.
Age bracket. Just use something like 18 to mean 18-25 or A-T meaning eighteen, or 1821... or take 1 off every number giving you 0710. Whatever floats your boat.
Creative name,doesn't matter.
Angle - just use something that makes sense to you. You're not going to have 6000 angles in your stats.
Targeting - easy, just use something that makes sense to you only. Targeting people who like Nike? Just use "do" which you know means "Just Do It" = Nike.
Bidding mode - this doesn't give much away at all so just use C for CPC, O for OCPM, M for CPM.
Ad type - again, obvious to anyone spying so who cares. This kind of stuff is all just for your own benefit. Remember that anyone who wants to spy on you is going to get a lot of insight by seeing the ads, clicking links and tracking http headers anyway.
You can pass these to a landing page then remove them from the URL in the address bar by using some PHP coding but again it's really pointless - it will be obvious in the http headers anyway.
Lastly, you could always use API-based platforms (e.g. PoFPro) that track all this data anyway with no need to pass stuff in the URL to a tracking system, other than what you want to use on landers or give to the network.